Although the prevalence of family-friendly policies in US workplaces has increased dramatically in recent years, few have been studied using scientifically sound designs. To address this critical gap, NIH and CDC formed the Work, Family, and Health Network (WFHN). During Phase 1, WFHN designed and conducted multiple pilot and feasibility studies. For Phase 2, the WFHN has been called upon to implement an innovative intervention based on Phase I pilot studies that is designed to increase family-supportive supervisor behaviors and employee control over work, and to evaluate the intervention using a group randomized experimental design. The goal of the proposed study is to assess the effects of a workplace intervention designed to reduce work-family conflict, and thereby improve the health and well being of employees, their families, and their workplaces. The study intervention is grounded in theory from multiple disciplines and supported by findings from our pilot/feasibility studies. We will assess the efficacy of the intervention via group-randomized field experiments, one at each of two employers representing different industries. Within each industry partner, 30 worksites of 50-120 employees each will be randomly assigned to intervention or usual practice conditions. All employee and supervisor participants will be assessed at baseline and at 6-, 12-, and 18-months post baseline, including survey interviews and health assessments of cardiovascular risk and sleep dysregulation based on selected biomarkers and actigraphy. Employees' spouse/partners and/or children (one resident child per employee) aged 10-17 years will be assessed to document the impact of the intervention on family functioning. In addition, to illuminate how the intervention affects the well-being of employees and their children, the Penn State team will study a sub-sample of 500 employee-child dyads (250 intervention and 250 control) who will participate in a daily diary assessment. At baseline and 12 months, employee and child will be interviewed by telephone on 8 consecutive days and will provide 4 separate saliva samples across the day on 4 call days; these will be assayed for stress hormones as more objective health indicators. A diary design moves the focus from between-person patterns of association linking work experiences and health to studying how day-to-day variations in employees' access to intervention-targeted workplace policies and practices are linked to corresponding variations in employees' daily health and family experiences, and in turn, those of their child. The proposed study's process evaluation will document details of intervention implementation and dose received by participants. Finally, the WFHN will translate findings to business environments and other public media channels. As a whole, this study holds great promise for informing the implementation of evidence-based family-friendly policies, and therefore improving the health and well-being of employees and their families nationwide.